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1   /****************************************************************
2    * Licensed to the Apache Software Foundation (ASF) under one   *
3    * or more contributor license agreements.  See the NOTICE file *
4    * distributed with this work for additional information        *
5    * regarding copyright ownership.  The ASF licenses this file   *
6    * to you under the Apache License, Version 2.0 (the            *
7    * "License"); you may not use this file except in compliance   *
8    * with the License.  You may obtain a copy of the License at   *
9    *                                                              *
10   *   http://www.apache.org/licenses/LICENSE-2.0                 *
11   *                                                              *
12   * Unless required by applicable law or agreed to in writing,   *
13   * software distributed under the License is distributed on an  *
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
15   * KIND, either express or implied.  See the License for the    *
16   * specific language governing permissions and limitations      *
17   * under the License.                                           *
18   ****************************************************************/
19  
20  
21  
22  package org.apache.james.util.watchdog;
23  
24  import java.io.IOException;
25  import java.io.OutputStream;
26  
27  /**
28   * This will reset the Watchdog each time a certain amount of data has
29   * been transferred.  This allows us to keep the timeout settings low, while
30   * not timing out during large data transfers.
31   */
32  public class BytesWrittenResetOutputStream extends OutputStream {
33  
34      /**
35       * The output stream wrapped by this method
36       */
37      OutputStream out = null;
38  
39      /**
40       * The Watchdog to be reset every lengthReset bytes
41       */
42      private Watchdog watchdog;
43  
44      /**
45       * The number of bytes that need to be written before the counter is reset.
46       */
47      int lengthReset = 0;
48  
49      /**
50       * The number of bytes written since the counter was last reset
51       */
52      int writtenCounter = 0;
53  
54      public BytesWrittenResetOutputStream(OutputStream out,
55                                           Watchdog watchdog,
56                                           int lengthReset) {
57          this.out = out;
58          this.watchdog = watchdog;
59          this.lengthReset = lengthReset;
60  
61          writtenCounter = 0;
62      }
63  
64      /**
65       * Write an array of bytes to the stream
66       *
67       * @param b the array of bytes to write to the stream
68       * @param off the index in the array where we start writing
69       * @param len the number of bytes of the array to write
70       *
71       * @throws IOException if an exception is encountered when writing
72       */
73      public void write(byte[] b, int off, int len) throws IOException {
74          out.write(b, off, len);
75          writtenCounter += len;
76  
77          if (writtenCounter > lengthReset) {
78              writtenCounter = 0;
79              watchdog.reset();
80          }
81      }
82  
83      /**
84       * Write a byte to the stream
85       *
86       * @param b the byte to write to the stream
87       *
88       * @throws IOException if an exception is encountered when writing
89       */
90      public void write(int b) throws IOException {
91          out.write(b);
92          writtenCounter++;
93  
94          if (writtenCounter > lengthReset) {
95              writtenCounter = 0;
96              watchdog.reset();
97          }
98      }
99  
100     /**
101      * Flush the stream
102      *
103      * @throws IOException if an exception is encountered when flushing
104      */
105     public void flush() throws IOException {
106         out.flush();
107     }
108 
109     /**
110      * Close the stream
111      *
112      * @throws IOException if an exception is encountered when closing
113      */
114     public void close() throws IOException {
115         out.close();
116     }
117 }